pstarr wrote:The article in question/this discussion is not about storage, but rather energy carriers, solar-based synthetic fuels.
Both approaches are being pursed. Using the process for energy storage to smooth out intermittent renewables and for producing an energy carrier to power vehicles.
In Germany two demonstration power-to-gas (P2G) plants designed to store excess electricity generated by renewable sources have begun operation. The amount of electricity generated each year by renewables is rising, but the intermittency of some of these sources, such as wind and solar, poses challenges for the grid. Banking excess electricity to feed into the grid at a future point, when it is needed, can be achieved using various storage technologies such as batteries. However, P2G plants open up the possibility of using this excess energy in different ways. In Germany, which has the largest installed capacity of wind and solar, several demonstration P2G plants are being evaluated for their smart grid potential.
The plant will bank excess power that is generated by wind farms, producing about 360m³ of hydrogen an hour. The hydrogen will be fed into the natural gas pipeline at around 2% by volume, at a maximum operating pressure of 55bar, effectively storing and transporting surplus renewable energy. After converting excess wind energy to hydrogen, the plant uses the hydrogen and biogas to generate heat and power. An alkaline electrolyser is used in the plant, which has been operational since 2011.
Future
By the latter part of this decade P2G could start to establish itself as a flexible storage technology in power grids as more electricity is produced from renewable sources.
Wind Power-to-Gas (P2G) technologyI see both efforts as worthwhile: Using the process to smooth out intermittent electricity generation and also producing synthetic fuels to run ICE vehicles. If we can turn renewable energy, CO2, and H2O into synthetic fuel, why would you find this to be objectionable? Even if only 90% of the energy generated ends up as energy carried in the final fuel, we are still coming out ahead because solar pv & wind have much higher EROEIs than 1.1:1.
pstarr wrote:Biofuels are a efficient conversion from sun to liquid fuel, probably with less losses than any industrial process, including the method outlined. (That is why Bush mandated it. But of course he was wrong because of the scope and also the limited eroei)
The only inputs we are talking about here are CO2, H2O, and energy. Biofuels have additional inputs. Trying to scale up biofuel production to replace current liquid fuel needs would exacerbate existing problems like topsoil depletion, dwindling phosphorus resources, etc.